Mechanical pencil



April 21, 1931. c. R. KEERAN MECHANICAL PENCIL Filed Feb. 25. 1929 Patented Apr. 21, 1931 UNITED STATES PATENT OFFICE,

' CHARLES It KEERAN, or EvANs'roN, ILLINOIS, 'AssIGNon To ROBERT N. BURTON, or CHICAGO, ILLINOIS I MECHANICAL PENCIL I Application led February 25, 1929. Serial No. 342,381.

This invention relates to mechanical pencils, and more particularly to pencils of the I propel-repel type .employing relatively long leads. The main object of this invention is to provide an improved operating mechanism, adaptedto facilitate and insure engagement by the mechanism of a new lead when inserted through the tip. A further object is to provide an improved construction, wherein access may be had to the spare lead chamber without dismantling the main operatin parts. It consists in certain features an elements of construction, in combination as herein shown and described, and as indicated by the claims.

In the drawings:

Figure 1 is an enlarged axial section through a mechanical pencil embodying this invention shown broken to condense the view; the plunger being showny at the limit.

of lead propelling movement and with the lead completely ejected.

Figure 2 is a longitudinal section through the pencil, with, certain parts shown in full.

Fi ure 3 is an enlarged fragmentary longitu inal section of the lowerportion of the pencil, showing the plunger at an intermediate position;

Figure 4 is a fragmentary longitudinal section, showing' the plunger and sleeve at the upper limit of movement. Figures 5, 6, 7 and 8 are transverse sectional views taken substantially as indicated at lines 5 5, 6 6, 7-7 and 8-8 respectively, on Fig. 1.

Figure 9 is a eraser sleeve.

Figure 10 is a longitudinal sectional view perspective view of the through a encil of slightly modified conthe of wall. The end of said tapered portion 11 is internally threaded to receive the threaded,

shank, 13, of a metallic terminal tip portion, 14. Secured in the shank portion 13 vis a bushing, l5, having a flange,.16, seated tending guide tube, 17 concentrically dis-- posed in the bore of the barrel and having its upper end closed and terminating adjacent the upper end of the barrel. Said guide tube is formed with a longitudinal slot, 18, which extends from the bushing to adjacent the closed upper end of the tube, while thelower end portion of said guide tube is formed as a clutch, composed of a plurality of outwardly movable spring fingers, 19, extending into the terminal tip portion, 14, below the bushing 1:5, the Aterminal tip portion, 14, being chamhered at 20 to provide clearance for said fingers.

Longitud-inally reciprocable in the guide tube is a-cylindrical sleeve, 23, whose lower e'nd is formed to frictionally grip a lead, 24, and adapted to act as a carrier therefor during its movement in either downward or up ward direction. It is to be understood that the sleeve is made of any suitable metal and has its lead-engaging end provided with one or more longitudinal slits so that the portions intermediate the slits act as yielding tangs'or clutchv fingers for producing suicientfrictio'n to retaina lead therein. Dis posed in the sleeve is a plunger, 25, which primarily serves to impart axial movementl to the lead carrier sleeve, and to also effect propelling through the tip terminal of the nal portion of the lead, as will hereinafter be described. Said sleeve is formed with a relatively short longitudinal slot, 26, which registers with the slot 18 in the guide tube 17, and through which slots projects a laterally extending driving lug, 27, of said plunger, which is cooperatively engaged with an internally threaded rotary tubular member 28, concentrically surrounding said guide tube and sleeve and positioned in spaced relation tothe inner wall of the barrel to form an annular chamber or magazine, 29, for the spare leads, 30. VThus the ool gage the end of the sleeve, as may slot 26 permits a limited range of axial movement of the plunger and sleeve with respect to each other. As will hereinafter more clearly appear, the rotary movement of the tubular member 28 with respect to the barrel causesthe plunger to be shifted axially therein, carrying the ysleeve with it.

The plunger is normally-yieldingly maintained retracted in the sleeve 23 with-` the lead engaging end of the plunger, positioned a substantial distance within the lead engaging end of said sleeve, as shown in Fig. 3, and at this position the lug 27 is at the upper limit of the slot 26. The means for yieldingly maintaining these parts in such relation, includes an extension, or tail piece, 33, on said plunger beyond the lug 27, which extension is slightly deformed to act as a spring--urged into frictional engagement with the inside of the sleeve; the extreme lend of said portion 33 being bent outwardly to form a hook terminal, 34, adapted to enbe seen in Figs. 3 and 4.. Thus, due to this resilient connection, movement is imparted to the sleeve by the plunger in lead propelling direction, and in the reverse direction, the movement of the sleeve with the plunger is made positive by the lug, 27, engaging the upper limit of the slot, 26.

It will now be apparent in connection With the drawings, that .through the major portion of the lead propelling operation, the plunger and sleeve remain in the relation to each other shown in Figs. 3 and 4, but during the propelling of the short remnant of the lead, the lower end of the sleeve encounters a stop shoulder, 37, in the tip terminal, 14, thus arresting its movement; and the continued forced movement of the plunger by rotation of the tubular member 28 overcomes the reaction of the yielding spring portion 33, and the hook terminal 34, so that the plunger may continue its axial movement to propel the final or remaining portion of leadthrough the tip. An annular bead, 38, is formed on the sleeve adjacent the lower end, and positioned for contactual engagement with the spring clutch fingers, 19, of the guide tube, when said sleeve abuts against the shoulder 37, in which position the clutch fingers yieldingly oppose retraction of the sleeve in lead retracting direction. However, when reloading by inserting a new lead through the tip, the plunger 1s first backed up and retracted a short distance in the sleeve which yieldingly held stationary by the clutch lingers engaging the bead 38, andthe lead is then frictionally engaged in the end of the sleeve; the deslred extent ofretraction of the plunger is indicated to the user when the spring portion 33 and terminal hook 34 snaps over the l v end of the sleeve.

`If this action should not be noted, the

continued forced retraction of the plunger merely moves the sleeve farther into the barrel, causing the bead 38 to spread the fingers 19 outwardly and release the sleeve; the lead may then be inserted in the sleeve and further retraction of the sleeve and plunger draws the lead back in position for use. However, it may be frequently desirable to permit the sleeve to be yieldingly held at its forward limit of'movement so as to be capable of engaging the end of a relatively short piece of lead. It is to be understood that the internal diameter of the guide tube 17 at all points is of a size to insure clearance and unobstructed movement for the bead 38 of the sleeve when telescoped therein. To prevent the sleeve and plunger from being shifted out of proper operating position with respect to each other whenretracted to the upper limit in the guide tube, the end of the sleeve is chamfered or beveled at 39 so that a portion of the sleeve projects beyond the hook terminal, 34, for encountering the closed end of the guide tube, as shown in Fig. 4.

Although this construction is especlally suitable for using relatively long leads, leads of various lengths, including short pieces, may be operatively inserted with the same facility as a long one; and the construction is such as to be ready to receive a lead at any position of the sleeve in the barrel provided only that the plunger has been retracted 1n the sleeve the necessary distance, as above described.

The rotary tubular member, 28, extends a substantial portion of the length of the barrel, and isprovided with bearing support at its lower end against the flange, 16, of the bushing; the upper end of said tubular member having an interlocking connection to the base wall, 41, of the tubular operating head, 42, by means of which the tubular member 1s rotatable in the barrel. A washer or bushing, 43, is provided in the tip portion 11, serving to support and guide the tubular member and also serving as a bottom for the spare lead chamber. This washer has its peripheral edge serrated so as to be firmly wedged in fixed position in the barrel. The location of this washer is such as to insure against wedging of the leads in the tapered tip, and yet provide a relatively long spare lead chamber, of substantially the same length as the longest lead that may be used in the mechanism.

Secured in the upper end of the barrel is a sleeve 45 having a portion extending outl of the barrel and formed with a bead 46 loosely spun over an annular bead 47, formed as a continuation of 'the bottom wall 41 of the head 42. Thus the operating head is swivelly locked to the barrel, forming a complete housin for the operating mecha nstn, which nee never to'v be disassembled unless for repair purposes. The bottom wall 41 of the head is formed with an aperture, 48, affording access to thespare lead chamber; to complete the closure of the spare lead chamber and insure against breakagefof the leads, 30, that might accidentally extend into and be caught by the aperture while the vhead and tubular member, 28, are being rotated relative tothe barrel, I provide a boss, 49, substantially occupying the aperture, so as to present a relatlvely iush inner surface of the base Wall 41 in the chamber. This projection 49 is formed as a depressed portion in the bottom of a tubular eraser sleeve, 50, which is adapted to be telescoped into the tubular operating head, 42, as shown in Fig. 1'. This sleeve and tubular head are formed with cooperating tongue and groove connections to facilitate and insure correct registration of the lboss with aperture'48. These include a pair of segmental inwardly extending annular beads, 51, lformed in the w-all of the tubular head adjacent the bottom, and spaced so as to form gaps of unequal extent. The lower end of the eraser sleeve 50 has cut-away portions, 52, correspondingly located, sothat the sleeve may adjustment.

be seatedwith the remaining wall portions fitted between thebeadsl in the head in only one possible in Figs.v 5 to 7. l

Telescoped in the eraser sleeve is an eraser position as ma be seen socket, 55, ofthe spring prong type, in

which is gripped an eraser, 56; the sleeve serving to compress the' prongsl into the eraser for securing it in any position of The portion of the sleeve 50 extending beyond the head 42 is formed as a ange 57 to aord a convenient finger grip to remove the sleeve with the eraser and socket as a unit for access to the spare lead chamber. An ornamental cap, 58, is telescoped onto the operating head, completely enclosing the upper endof the pencil.

Fig. 10 illustrates a modified construction which is to be understood as being provided with substantially the same operating mechanism as above described. In this construction the operating head, 42, is swivelly connected to a ferrule, 61 which is threaded onto the upper end of the barrel 10a, so that if desired, the entire head together'with the threaded tubular member 28a may be quickly and easily removed from the barrel.

The lower end -of the threaded ltubular member is centered and supported in a bearing 16h, disposed in the tip ofthe barrel and abutting a ainst the flange, 16, of the bushing, 15a., oncentrically disposed about the tubular member 28a is a partition tube, 62, fixedly secured in the barrel in spaced relation to its .inner wall/to form a spare lead magazine 29u opening at' the, up er end of thebarrel. Reinforcing' said tube 62 is -a washer, 63, firmly lodged in the barrel, and

1. In a mechanical pencil havinga barrel and a tapered tip, a guide tube disposed in the barrel and extending a substantiallength of the pencil, a sleeve disposed concentrically therein and mounted for reciprocation in said tube and having its lower end formed to frictionally engage a lead, and a plunger disposed in the sleeve and axially movable therewith in the guide tube in propelling a lead in either direction, said sleeve and plunger being interconnected to provide a limited range of axial movement ofv one part With respect to the other, said sleeve being dimensioned to engage a stop in the tip for limiting its axial movement in the propelling downward direction before the plunger movement is 'completed; said sleeve and guide tube having co-operating features, engageable at such limit of movement of the sleeve temporarily opposing upward movement of said sleeve to permit the plunger to first be withdrawn into the sleeve.

2. In the combination defined in claim 1, one 'of said co-operating features being adapted to yield radially to permit retraction of the sleeve in the guide tube upon forced axially movement of the plunger.

3. lIn the combination defined in claim 1, said co-operating features including a radially extending projection on the sleeve, andv a'radially movable resilient portion o n the guide tube.

.4.'In the combination defined in claim 1,

said co-operating features including an annular bead on the sleeve, and a plurality of radially yielding fingers at the lower end of gage the lead, a plunger in the sleeve axially 7 movable therewith in the guide tube for propelling a lead in either direction, means for causing such movement of the sleeve and plunger, said sleeve and plungerfhaving a lost motion connection to permit limited axial movement of one part with respect to the other, said tip being formed with a stop to limit the axial movement of the sleeve in a downward direction and causing the sleeve .to be arrested with its lead-engaging end within said tip, and means normally main-v taining 'the plunger at the retracted limit of movement in the sleeve, and releasable.

plunger may feed the remnant of the lead through the terminal portion of the tip.

6. In a mechanical pencil having a barrel and a tapered tip provided with a rigid terminal portion through which a lead is guided, a guide tube disposed in the barrel and extending a substantial length of the pencil, a sleeve concentrically disposed in said tube and reciprocable therein and having its lower end formed to frictionally engage a lead, a plunger in the sleeve axially movable therewith in the guide tube for propelling a lead in either direction, means for causing such movement of the sleeve and plunger, said sleeve and plunger having a lost motion connection to permit limited axial movement of one part with respect to the other, said tip being formed with a stop to limit .the axial movement of the sleeve in downward direction and arresting the sleeve with its lead-engaging end within said tip, said plunger and sleeve being dimensioned so that at one limit of movement of the respective parts the lead-contacting end of the plunger is retracted a substantial distance within the rictional lead-engaging endof the sleeve, and means for yieldingly maintaining said plunger in such relation to the sleeve, and adapted when the sleeve is arrested by the stop in the tip to permit Vcontinued axial movement of the plunger beyond the lead-engaging end of the sleeve for propelling the remnant of the lead downwardly through said tip terminal. y

e 7. In the combination defined in claim 6, said yielding means including a resilient hook portion on said plunger adapted to engage against tlie upper end of the sleeve.

8. In a mechanical pencil having a barrel and a tapered tip, a guide tube disposed in the barrel and extending through a substantial part of the length of the pencil, the upper end of said tube being formed to provide a stop, a sleeve concentrically disposed in said tube and reciprocable therein and having its lower end formed to frictionally engage a lead; a plunger in said sleeve, axially movable therewith, in said guide tube for ropelling a lead in either direction, means or effecting such movement, said sleeve and plunger being inter-connected to permit a limited range of axial movement with respect to each other, and means normally tending to retain said plunger at the retracted limit of movement in the sleeve, said means including an outwardly extendinr resilient hook portion at the upper end o? the plunger and adapted to engage the upper end of the sleeve; said upper end of the sleeve being bevcled'to provide a portion projecting beyond said hook portion and adapted to abut lagainst the stop in the guide tube for limiting the retraction therein of the sleeve.

9. In a mechanical pencil, a barrel, a

threaded tubular member concentrically disposed in the barrel, a slotted guide telescoped within said threaded member and rigidly secured to the barrel adjacent its lower end, a head rotatively engaged with the barrel and fixed to the threaded tube for turning it, a lead-propelling plunger longitudinally movable in the slotted guide and having a driving lug projecting through the slot thereoI for engagement with the threaded tube, together with a lead-gripping sleeve carried on the plunger and slidable longitudinally through a limited range thereon, said sleeve being positivel engaged with the plunger at the limits o such range and extendable beyond the lower end of the plunger for engaging a lead, and stop means in the barrel for arresting movement of the sleeve adjacent the lower end'of the barrel and permitting the plunger to slide through the sleeve in lead-propelling direction.

10. In the combination defined in claim 9, stop means fixed with respect to the barrel, positioned to hold the sleeve at its lower limit therein until the plunger is retracted within the lower end of the sleeve.

1l. In a mechanical pencil having a barrel provided with a longitudinal bore, a tube supported concentrically in said bore in spaced relation to form an annular s are lead chamber, a tubular head having alluottom wall rigidly secured to the upper end of the tube and disposed to close the end of the chamber, said bottom wall being provided with an aperture affording access to the chamber, and a sleeve telescopically associated with the head and having a bottom portion provided with a boss formed to extend into and seat in said aperture to complete the closure of the s are lead chamber.

12. In the combination defined in claim l1, said boss occupying the entire a erture and presenting a surface substantial y flush with the surface of said bottom wall which faces toward the chamber.

13. In the combination defined in claim 11, means for positively registering the boss of the sleeve with the aperture of the head as the former is telescoped intothe latter.

14. In the combination defined in claim 11, said tubular head and sleeve having inter-engaging tongue-and-groove features for insuring registration of the boss with the aperture as the sleeve is telescoped into the head.

l5. In a mechanical. pencil, abarrel, atubular member rotatably supported concentrically in the bore of the barrel in spaced relation to form an annular spare lead chamber, a tubular head having a bottom wall rigidly secured to the tubular member, and positioned to close the end of the spare lead chamber, said head and barrel having a swivel connection whereby said head and tubular member are rotatable together with respect to said barrel, said bottom Wall of the head having an aperture therein aording access` to said lead chamber, a sleeve telescopically associated with the head, ro-

vided with a bottom portion having a oss adapted to register with the aperture for completing closure of said spare lead cham-- ber, means for insuring registration of said boss and said aperture when the sleeve is telescoped into the head, and a yieldable eraser gripping socket adapted to be telescoped into said sleeve, said sleeve serving to compress said eraser socket forv gripping its eraser in any position of adjustment.

16. In a mechanical pencil a barrel, a

threaded tubular member concentrically disposed in said barrel, a head rotatively enn gaged with the barrel and fixedly secured 4ed tub l the barrel adjacent its lower end, a leadto said tubular member for turning it, a slotted guide telescoped within said threadu ar member and rigidly secured to propelling plunger longitudinally movablev in the slotted guide and having a driving lug projectingthrough the slot thereof for cooperative engagement with the threaded tubular member, a lead-gripping sleeve carried on the plunger and axially movable therewith in the slotted guide, said sleeve and plunger having a lost motion connection to permit limited axial movement of one part with respect to the other, stop means in- 17. In a mechanical pencil having a barrelV and rotatable head and a`. lead propelling mechanism in the barrel, said mechanism consisting of a slotted guide tube within a V'spiral member and a plunger in the slotted tube having engagement with the spiral memberI through t e slot, together with a lead holding sleeve telescoped over said plunger and slidable therewith in theslotted tube, said s iral member being rigidly connected to said head and rotatable in the barrel, and said slotted tube being rigidly mounted in the barrel, means permitt' limited telescopic movement between the plun er and the sleeve, and means independent o the spiral for holding the plunger and sleeve in normal working position with the end of the plunger 'retracted the sleeve.

CHARLES B. KEERAN.

eeve in feeding the remnant of the lead 

